SmartGit is an easy-to-use graphical user interface for Git with optimized work-flows. SmartGit supports all Git and Mercurial features needed for every-day work in software development projects:

Local working tree operations

Status, diff, log

Push, pull, fetch (for all protocols)

Tag and branch management

Merge, cherry-pick, rebase, revert

Submodule support

Stash management

Remotes management

I has also an easy to use wizard to connect you to online repositories like GitHub and BitBucket

RabbitVCS

In contrast, RabbitVCS has a different approach from other tools. Rather than providing an external UI for your git repository, it integrates its self to Nautilus. In fact RabbitVCS is a set of graphical tools written to provide simple and straightforward access to the version control systems you use.

I am quite partial to smartgit. You can read more about it here It's by far the most complete git client on Linux that I have found. That being said, there is real strength in the command line, and I suggest you learn it well before using a GUI.